Target Exam

CUET

Subject

Physics

Chapter

Laws of Motion

Question:

At any instant of time $t$, the displacement of any particle is given by $2t-1$ (SI unit) under the influence of force of $5\,N$ . The value of instantaneous power is (in SI unit):

Options:

10

5

7

6

Correct Answer:

10

Explanation:

The correct answer is option (1) : 10

To find the instantaneous power delivered by a force, we can use the formula:

$P=\vec{F}.\vec{v}$

where $P$ is the power, $\vec{F}$ is the force vector, and $\vec{v}$ is the velocity vector of the particle.

In this question, the force exerted is given as a constant $5\, N$. Since no direction is specified, and the displacement is given in a scalar form, we assume the force acts along the direction of displacement. Therefore, we can treat the vectors as scalars for simplicity.

The displacement of the particle is given by:

$x= 2t-1$

The velocity, $\vec{v}$ , is the derivative of displacement with respect to time. Deriving the displacement equation with respect to time $t$ gives:

$v=\frac{dx}{dt}=\frac{d}{dt}(2t-1)=2$

The instantaneous power can now be calculated as:

$P=F.v=5 × 2= 10\, Watts $

Thus, the instantaneous power delivered by the force at any time t is 10 Watts.

The correct answer is Option 1 : 10.